The substitution of lightweight roof panels for the low-carbon steel or steel alloy roof panels most commonly used in motor vehicles is an attractive option for vehicle mass reduction. Often, however, the remainder of the vehicle body structure is fabricated of a dissimilar material. The joining of dissimilar materials can be problematic. For example, joining an aluminum or aluminum-based alloy roof panel to a steel body panel may be difficult due to the thermal expansion considerations of the dissimilar materials. The combination of the aluminum roof panel attached to the steel body may create compressive stresses in the aluminum roof panel when subjected to elevated temperatures.